Thursday, June 06, 2013

Andrea, The First Storm Of The Season

Cape Hatteras, North Carolina

It is that time of year for those of us who live on the North Carolina coast.  The first storm with tropical characteristics is headed up the coast.

When you live just up the river from Swansboro, North Carolina, it is impossible to ignore coastal storms.  Yet in the almost seven years that we have lived just  a few miles from the Atlantic Ocean, we have managed just one serious storm, Irene, and a brush with Sandy.

As most coastal residents will tell you, beyond the line of homes that are oceanfront or right on the sounds, the areas which get the most damage are often far inland.  Once you get fifty miles inland, rivers do not have the size to handle the torrential downpours that often result from tropical storms.

We live three miles up the White Oak River and the river is between one and two miles wide depending on where you measure it.  It is also a tidal river.   When our tides go out, we lose a couple of feet of water.  If a hurricane is going to hit us and cause flooding like Irene did, it has to hang around for a while.

The worst flooding that we have endured here on the Crystal Coast came from a freak rainstorm in September 2010.  If you compare these pictures with ones from Hurricane Irene, it is a little hard to tell, but I can guarantee you the rainstorm flooding was worse.  Of course there are not many rainstorms that deliver 20.25 inches of rain in less than eight hours.

Fortunately when our nearly two foot tide went out, our flooding from the rainstorm disappeared. If a hurricane surge hits at high tide, it can cause more problems but hurricane flooding is very complex once you get into the coastal rivers.  Wind direction and the angle of the river in relation to the storm's track become very important.

Sometimes a storm surge goes right by an inlet because of the direction of the wind.  Those of us living in newer homes take some consolation from the fact that our houses are built above the level of one hundred year floods, but you still know that the possibility of flooding is always there.

On the flip side of tropical storms is the beneficial moisture that they often provide.  Our area was extremely dry during the month of May.  We received only one third of an inch rain in the whole month.  While the sunny skies were great for vacationers, they were a problem for those growing crops.  Fortunately we got eight tenths of an inch  of rain this first week of June.

That rain probably saved the area's corn crop, and if we get a nice dose of rain from this tropical system it will help us make it through June and into July.  Our sandy soils need about an inch of rain a week to keep our plants growing.  In that respect, we will welcome Andrea.

In July of 2011 it was so dry in Eastern North Carolina that we had some swamps which caught fire.  Given the choice of a scenario of swamps burning or rains from a tropical system, I will pick the tropical system.

Of course that choice is highly location dependent.  A few inches of rain are not a big problem with our sandy soils and river drains that are a couple of miles wide.  Tropical moisture has caused massive flooding in the mountain valleys near Roanoke, Virginia area where we used to live.  Mountains concentrate rain into narrow rivers which break from their banks when they run out of room.  Sometimes the flooding in narrow valleys can turn into deadly flash floods.

We will not take Andrea lightly since we have just returned from trip that took us from Ocracoke Island to Nags Head.  There are still some signs on the Outer Banks of the damage to Route 12 from last fall's brush with Hurricane Sandy. 

Whether Andrea ends up being welcome or unwelcome all depends on where you live.  We are hoping our spot on the Southern Outer Banks remains a good one to weather the storms which are a normal part of summer at the beach.